By ByteBot
WebAssembly runtimes are clocking sub-millisecond cold starts at the edge—100x faster than Docker containers. Fastly’s hitting 35 microseconds. Cloudflare’s eliminated cold starts entirely. The serverless edge computing that’s been promised for years is finally delivering, and it’s happening because platforms are ditching containers for WASM. 2025 is shaping up as the year edge serverless goes mainstream, fueled by a projected $124.52 billion market by 2034 and 75% of IoT solutions expected to use edge computing by year’s end.
The Proximity Paradox
Serverless edge computing had a fatal flaw: containers. You put servers closer to users to cut latency, then boot up a Docker container that takes 1-2 seconds to start. The geographic advantage evaporates when your application spends 1000+ milliseconds initializing an OS, loading a multi-megabyte image, and configuring networking before handling the first request.
This mattered less for traditional cloud serverless where you’re already accepting 50-100ms network hops. But at the edge, where you’re selling single-digit millisecond latency, a 1-2 second cold start is catastrophic. Real-time AI inference, IoT sensor processing, autonomous vehicle coordination—none of it works when your function takes longer to boot than to execute.
WebAssembly Breaks the 1ms Barrier
WebAssembly solves this by eliminating the container entirely. Instead of booting an OS and initializing a runtime, WASM executes in a lightweight sandbox that starts in microseconds. Fastly Compute@Edge reports 35.4 microseconds for instance instantiation—100x faster than competing serverless solutions. Cloudflare Workers achieves sub-1ms cold starts across 300+ global locations, effectively reaching zero spin-up time for production workloads.
The performance hierarchy now looks like this: Fastly at 35 microseconds, Cloudflare under 1 millisecond, generic WASM runtimes at 10-50 milliseconds, and Docker containers lagging at 1-2 seconds. That’s not incremental improvement. That’s a complete architectural shift.
The technical reason is straightforward. WebAssembly binaries are compact—typically under 50 KB compared to multi-megabyte container images. WASM runs in V8 isolates or specialized runtimes that instantiate instantly, with no operating system to boot. You get near-native execution speed with sandboxed security, but none of the overhead that makes containers slow at startup.
Production Workloads Running Today
This isn’t experimental. Cloudflare Workers is handling AI inference at 15ms for small models, with large model inference running 8x faster than TensorFlow.js (189ms vs 1500ms). Fastly’s customers are processing billions of requests monthly with P99 latency under 5 milliseconds. Akamai’s positioning WebAssembly as the foundation for their next-generation edge platform. WasmEdge, the open-source runtime, benchmarks at 20% faster execution than containers on top of the 100x startup advantage.
These platforms aren’t pilots. They’re production infrastructure serving massive scale. The “experimental” label expired in 2024. We’re now in the deployment phase.
Use Cases That Actually Work
The sub-millisecond cold starts unlock applications that were non-viable with container-based serverless. Real-time AI inference at the edge, where Cloudflare’s seeing 15ms response times for small models. IoT and 5G workloads requiring instant sensor data processing for autonomous vehicles, smart manufacturing, and remote healthcare. Media processing like image resizing and video transcoding happening at the edge instead of round-tripping to centralized cloud infrastructure.
Smart cities are a major driver—traffic management, surveillance analytics, real-time decision systems. With 75% of IoT solutions expected to incorporate edge computing by 2025, the demand for instant-response serverless is accelerating. WASM’s speed makes these workloads economically viable by processing data locally instead of shipping it to distant data centers.
But it’s not a silver bullet. Simple operations like redirects or authentication checks run faster in pure JavaScript because there’s minimal compute to benefit from WASM’s advantages. Long-running processes are still better suited to traditional containers. Applications requiring extensive native OS libraries may hit WASI (WebAssembly System Interface) limitations. Know your use case before migrating.
Market Momentum Building
The edge computing market is projected to grow from $168.4 billion in 2025 to $248.96 billion by 2030. Edge serverless specifically is targeting $124.52 billion by 2034, up from $17.78 billion in 2025—a 7x expansion in nine years. The broader serverless market is climbing from $24.51 billion in 2024 to $52.13 billion by 2030, with edge deployments becoming the high-growth segment.
The drivers are clear: 5G rollout enabling real-time edge applications, IoT device proliferation creating massive data processing demand at the edge, and cost pressure pushing companies to process data closer to its source rather than paying for cloud round-trips. WebAssembly’s sub-millisecond cold starts are positioning it as the enabling technology for this shift.
Industry analysts are calling 2025 “the year WASM dominates edge and serverless.” The performance gap is too wide to ignore—100x faster cold starts aren’t a competitive advantage, they’re table stakes. Companies betting their infrastructure on WebAssembly aren’t taking risks. They’re reading the benchmarks and making the obvious call.
Docker revolutionized cloud computing by standardizing deployment. But at the edge, containers are the bottleneck, not the solution. WebAssembly is proving that microsecond cold starts and near-native performance can coexist with the portability and security that made serverless attractive in the first place. The platforms are live, the workloads are running, and the market is responding. The edge is finally as fast as it should be.
